Brake



March '15, 193s.

H. G. AXTMANN BRAKE Filed Aug. l, 1935 2 Sheets-Sheet l INVENTOR. HAreoLD Q. Afm/vwlA BY ATTORNEX 15, 1938. H. G. Ax'rMANN BRAKE Filed Aug. l. 1935 2 Sheets-Sheer, 2

INVENTOR. BY HAQOLD Q. AXTMANN i?. QWATTORNEY 67 Patented Mu. 15, 193s 2,111,503

UNITED STATES PATENT OFFICE BRAKE Harold G. Axtmann, River Grove, Ill., auignor to Bendix Products Corporation, South Bend, Ind., a corporation of Indiana Application August 1, 1935, Serial No. 34,236 a 18 Claims. (Cl. 18S-106) This invention relates to brakes and is illusthat there is shown a brake having a backing trated as embodied in a brake o f the internal plate 28, a brake drum 22, friction shoes 24 and expanding single anchor type wherein floating 428, and an anchor 28. At one end the shoes are friction shoes are used. notched so as to receive the notched ends of In my copending application Serial No. 625,494. an adjustmentl link 32 and a spring 44 connects 5 filed July 28, 1932, I disclosed an invention of the shoes together and engages the notched pean equal action cam intended to overcome dif riphery oi an adjustment wheel 48. ncultles previously had in providing an actuat- The other ends of the shoes each have a coning cam readily adapted to float with the shoes cave contour, and these ends are urged into enand actuating the shoes equal amounts regardgagement with the anchor 28 by any suitable 10 less of the direction of rotation of the brake. means such as a spring 48. Floatingly mounted Itis at times desirable to provide two separate on the anchor 28 is a cam lever 50. The lever means for applying such a brake. For instance, 58 has an arm B2 and at the end thereof is it may be desired to operate the brake either provided with a lug 54 by which it may beturned.

l5 hydraulically or mechanically. In applying the The lever 50 is also provided with lugs 88 which 15 principle of the equal action cam to a brake extend between the ends ci the shoes and which actuated by two separate applying means, diillare adapted (when the cam lever is turned) to cultles were encountered by reason oi the fact urge the shoes 24 and 28 away from the anthat it is highly desirable that each applying chcr 28.

9,0 means be allowed to remain in its neutral posi- In order that the cam lever 50 may float freely 20 tion while the brake is being actuated by the with respect to the anchor, a large slotted aperother applying means and in that the available ture 58 is provided therein so that the cam lever space within a brake drum is quite limited. i0 clears the anchor adequately during all normal It is accordingly an object of this invention operations of thebrake. To actuate the cam 25 to provide a brake applying mechanism having I provide a second lever 88 which is pivoted on 25 two separate actuating means and having apthe anchor as at 62 and which is formed with plying means tree to float with the brake shoes a cam surface 55 adapted to contact the lug 54 and so arranged that it corrects the errors in to actuate the cam lever Ill. I provide the lever the distances moved in the opposite directions 80 with arms 64 and 88, each of which is conof rotation. nected to a separate means of actuation. The 30 l A further object is to provide means to allow arm 84 is pivotally connected to a piston rod each of the applying means to remain in its 88 through which applying force may be exerted inactive position while the brake is being applied by a piston 10 working in a wheel cylinder 'l2 by the other applying means. secured to the backing plate 2li. The piston lll A further object is the elimination of parts is provided with a packing cup 14 which is held 35 and simplification of construction in such a in contact with the piston by a light spring 15. device, so that there may be adequate room The arm 68 is provided with a pin 16 which within the drum for the brake structure. extends through a slot 18 in a cable iltting 80 se- Further objects and features oi the invention cured to the end oi a flexible cable 82. The cabl will appear from a reading of the subjoined extends through a housing 84 secured to the 40 speciilcation and claims and from a considerabacking plate 20 and thence through the backtion of the accompanying drawings, in which: ing plate. There is interposed between the hous- Figure 1 is a view in section of a brake dising 84 and the iltting 88 a spring 86 for mainclosing one form of my invention; taining the cable extended except when a pull Figure 2 is an enlarged view in section taken is exerted on the cable in actuating the brake 45 on the line 2-2 of Figure 1; thereby.

Figure 3 is a view in section showing on an In the normal operation of the brake, iluid enlarged scale a fragment corresponding to a under pressure introduced into the cylinder 12 portion of Figure 1 and showing in detail the exerts force on the piston 18 which acting construction of the piston rod; through the rod 88 turns the lever 80 about its 5o Figure4isan enlarged fragmentary view showpivot on the anchor 28. The cam edge 55 ot ing an alternate form of my invention; and the lever contacting with the lug 54 turns the Flgure is another enlarged fragmentary view cam lever 80 and this spreads the shoes intp showing another modiiied form of my invention. drum contact floating with the shoes as they 55 Referring to Figures 1 and 2, it will be seen shift to anchor on one or the other shoe depend 55 ing on the direction of drum rotation. The pin 16 moves in the slot 18 while the spring 86 maintains the cable 82 extended.

For emergency operation or for parking, a pull may be exerted on the cable 62. This operates also to turn the lever 60 and thus spread the shoes in a manner similar to that just described above. However, the piston rod 68 in this case moves away from contact with the piston 1U, the air pressure on the outer face of piston maintaining it in the position shown.

The piston rod may be formed as shown in Figure 3 in order to determine more surely and definitely the return position of the piston, and to prevent the suction of air into the cylinder. 'Iherein the rod |68 is formed of a pair of telescoping sleeves |61 and |68 and interposed between the sleeves is a compression spring |65. The piston |10 is provided with a flange |1| which coacts with the outer end of the cylinder |12 to determine the released position of the piston. The spring |65 should be stronger than the spring 15, but weaker than the spring 48.

In the arrangement shown in Figure 4, the lever 260 pivoted on the anchor 228 has an oppositely extending arm 26| which contacts the lug 254 and the lever 266 which is entirely separate from the lever 260 and is separately pivoted on the anchor 228 also contacts the lug 254. The lug 254- which is relatively long, is carried by the floating cam lever 250. The cam lever thus may be operated either by a piston through the piston rod 268 and the lever 260, or by a cable such as the cable 282 through the 1ever266. 'I'he floating lever is formed with lugs 256 which are interposed between the ends of the brake shoes 224 and 226.

In the form shown in Figure 5, the lever 360 is pivoted on the anchor 328 and is formed with an arm 364 which is pivotally connected to the piston rod 368 and with a short arm 366 to which there is pivoted at 361 the auxiliary lever 369. The auxiliary lever 369 is arranged normally to bear on the arm 366 at 31| and when the lever 369 is operated by a cable (382) actuates the lever 360. The floating cam lever 358 carries the shoe actuating lugs 356 and a third lug 354. The lug 354 normally bears on the cam surface 355 of the lever 360 and the cam lever 350 is thus operated by movement of the lever 360 to spread the shoes 324 and 326.

It is to be understood that the above described embodiments of my invention are for the purpose of illustration only and various changes may be made therein without departing from the spirit and scope of my invention.

I claim:

1. A brake comprising a support, a floating friction means, a floating lever mounted between the ends of said friction means, two separate means for actuating said floating lever, one of said operating means comprising a cylinder and piston, and means comprising a spring interposed between said lever and the piston for maintaining said piston in its inactive position even though the brake is being applied by the other operating means.

2. A brake comprising a backing plate, an anchor secured to said backing plate, a floating friction means, a floating lever mounted between the ends of said friction means, and two separate means for actuating said floating lever, said separate means each including a lever pivoted on said anchor.

3. A brake comprising a backing plate, an

anchor secured to said backing plate, a floating friction means, a floating lever mounted between the ends of said friction means, and two separate means for actuating said floating lever, said separate means each including a lever pivoted on said anchor, and said floating lever carrying a lug adapted to contact with either of said other levers.

4. A brake comprising a drum, a support, a floating friction means, an actuating means comprising a. lever floatingly mounted between the ends of said friction means, a lever mounted on a pivot fixed relative to said support, means where by said fixed pivot lever operates said floating lever, and two separate means for operating said fixed pivot lever.

5. A brake comprising a drum, a support, a floating friction means, an actuating means comprising a lever floatingly mounted between the ends of said friction means, a lever mounted on a y pivot fixed relative to said support, means whereby said fixed pivot lever operates said floating lever, and two separate means for operating said fixed pivot lever, one of said levers carrying a lug and the other being provided with a cam surface with which said lug contacts.

6. A brake comprising a drum, a support, a floating friction means, an actuating means comprising a lever floatingly mounted between the ends of said friction means, a lever mounted on a pivot flxed relative to said support, means whereby said fixed pivot lever operates said floating lever, and two separate means for operating said fixed pivot lever, said fixed pivot lever having two arms one of which is connected to each of said operating means.

7. A brake comprising a drum, a support, a floating friction means, an actuating means comprising a lever floatingly mounted between the ends of said friction means, a lever mounted on a pivot fixed relative to said support, means whereby said fixed pivot lever operates said floating lever, and two separate means for operating said fixed pivot lever, said fixed pivot lever carrying an auxiliary lever. thereon connected to one of said operating means.

8. A brake comprising a drum, a support, a floating friction means, an actuating means comprising a lever floatingly mounted between the ends of said friction means, an anchor pin fixed relative to said support on which said friction means anchors, a ilxed pivot lever pivotally mounted on said anchor, means whereby said flxed pivot lever operates said floating lever, and two separate means for operating said fixed pivot lever.

9. A brake comprising a backing plate, an anchor secured to said backing plate, a floating friction means, a floating lever mounted between the ends of said friction means, and means for actuating said floating lever, said actuating-means including a lever pivoted on said anchor and arranged to contact said floating lever, a hydraulic cylinder having a piston, and a cable, said piston and cable being arranged to actuate said floating lever separately.

10. A brake comprising a backing plate, a floating friction means, a floating lever mounted between the ends of said friction means, a lever pivoted on said anchor for at times operating said floating lever, a hydraulic cylinder for at times operating said pivoted lever, and a cable connected to said floating lever.

HAROLD G. AXTMANN. 

